Present status of some virus diseases affecting legume crops in Tunisia, and partial characterization of Chickpea chlorotic stunt virus

Field surveys were conducted in Tunisia during the 2005-2006, 2006-2007 and 2009-2010 growing seasons to identify viruses which produce yellowing, reddening and/or stunting symptoms of chickpea, faba bean and pea crops. Tissue blot immunoassay (TBIA) results showed that Chickpea chlorotic stunt virus (CpCSV) was the most common virus, followed by Faba bean necrotic yellows virus, Bean leafroll virus and Beet western yellows virus. The coat protein (CP) gene nucleotide sequence of seven CpCSV isolates collected from different regions of Tunisia was compared with sequences of five other isolates in the NCBI database. A homology tree of the CP nucleotide sequences was prepared and CpCSV isolates were grouped into two clusters. The first group contained two Tunisian CpCSV chickpea isolates collected from Bizerte and Kef; sequenced regions showed a high nucleotiode homology (95%) to that of the Ethiopian and Sudanese CpCSV isolates. The second group included five Tunisian isolates: two from chickpea, two from pea and one from faba bean, which showed a high homology (96%) when compared with the Moroccan, Egyptian and Syrian CpCSV isolates.